Mask



FIG. 1 is a context view of the mask at a top oblique angle;

FIG. 2 is a side view of the mask in an open configuration from a first side;

FIG. 3 is a front view of the mask in the open configuration;

FIG. 4 is a side view of the mask in the open configuration from a second side;

FIG. 5 is a rear view of the mask in the open configuration;

FIG. 6 is a top view of the mask in the open configuration;

FIG. 7 is a bottom view of the mask in the open configuration;

FIG. 8 is a front view of the mask in a closed configuration; and,

FIG. 9 a side view of the mask in the closed configuration from the first side.

The broken lines in the drawings show environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 